ORA-29471: DBMS_SQL access denied

declare
   cur  integer;
begin
   cur := dbms_sql.open_cursor;
  
   dbms_sql.close_cursor(cur);
   dbms_sql.close_cursor(cur);
end;
/

declare
   c    number;
   stmt varchar2(1000);
begin
   dbms_sql.parse(c, stmt, dbms_sql.native);
end;
/

alter system set "_dbms_sql_security_level" = 384 scope=spfile;